Information Notice No. 89-48:Design Deficiency in the Turbine-Driven Auxiliary Feedwater Pump Cooling Water System
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
May 22, 1989
Information Notice No. 89-48: DESIGN DEFICIENCY IN THE TURBINE-
DRIVEN AUXILIARY FEEDWATER PUMP
COOLING WATER SYSTEM
All holders of operating licenses or construction permits for nuclear power
This information notice is being provided to alert addressees to a design
deficiency in a turbine-driven auxiliary feedwater pump cooling water system.
It is expected that recipients will review the information for applicability
to their facilities and consider actions, as appropriate, to avoid similar
problems. However, suggestions contained in this information notice do not
constitute NRC requirements; therefore, no specific action or written response
Description of Circumstances:
On April 13, 1989, the licensee for the Zion Station identified a design de-
ficiency in the turbine-driven auxiliary feedwater (AFW) pump cooling water
system. The deficiency was created when a modification was made to the
turbine-driven AFW pump in order to satisfy the AC power independence criteri-
on. This modification changed the pump's cooling water supply from the
service water system to the auxiliary feedwater system. The cooling water now
comes from the fifth stage leakoff of the AFW pump and is supplied to the
pump's lube oil cooler, the AFW turbine governor, and the AFW turbine bearings
at 75 psig by a pressure-regulating valve. The cooling water is then returned
to the AFW pump suction line. The deficiency would have occurred when the AFW
pump suction was aligned to its emergency supply (service water) rather than
its normal supply (the condensate storage tank). In this emergency lineup,
the suction pressure will increase to approximately 90 psig. Because the AFW
pump cooling water pressure would be below the AFW pump suction pressure, AFW
pump cooling water flow would be lost. This loss of cooling water flow could
eventually lead to overheating of the AFW pump turbine bearings and failure of
the AFW pump turbine.
.. IN 89-48
May 22, 1989
Page 2 of 2
The licensee made a temporary modification in the AFW pump cooling water
return line configuration to correct this design deficiency. A permanent
modification is under development for future installation.
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact: Jared Wermiel, NRR
Attachment: List of Recently Issued NRC Information Notices
May 22, 1989
Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No._____Subject_______________________Issuance_______Issued to________
89-47 Potential Problems With 5/18/89 All holders of OLs
Worn or Distorted Hose or CPs for nuclear
Clamps on Self-Contained power reactors and
Breathing Apparatus fuel facilities.
89-46 Confidentiality of 5/11/89 All holders of
Exercise Scenarios licenses for fuel
having an approved
89-45 Metalclad, Low-Voltage 5/8/89 All holders of OLs
Power Circuit Breakers or CPs for nuclear
Refurbished with Sub- power reactors.
89-44 Hydrogen Storage on the 4/27/89 All holders of OLs
Roof of the Control Room or CPs for nuclear
88-82, Torus Shells with Corrosion 5/2/89 All holders of OLs
Supp. 1 and Degraded Coatings in or CPs for BWRs.
89-43 Permanent Deformation of 5/1/89 All holders of OLs
Torque Switch Helical or CPs for nuclear
Springs in Limitorque power reactors.
SMA-Type Motor Operators
88-97, Potentially Substandard 4/28/89 All holders of OLs
Supp. 1 Valve Replacement Parts or CPs for nuclear
89-42 Failure of Rosemount 4/21/89 All holders of OLs
Models 1153 and 1154 or CPs for nuclear
Transmitters power reactors.
89-41 Operator Response to 4/20/89 All holders of OLs
Pressurization of Low- or CPs for nuclear
Pressure Interfacing power reactors.
OL = Operating License
CP = Construction Permit
Page Last Reviewed/Updated Friday, May 22, 2015